Improvement in steam-boilers



' S; SMITH.

STEAM-BOILER.

Patented my 23, 1876.

WW i

"-1 PETERS, PHOTO-LITHOGRAP UNI-TED STATES PATENT OFFIon.

SIDNEY SMITH, OF WORCESTER, MASSACHUSETTS.

' IMPROVEMENT IN STEAM-BOILERS.

Specification forming part of Letters Patent No. 177,760. dated May 23,1876; application filed September28,-1'875.

this specification, and represent, in-

Figurel, longitudinal section; Fig. 2, transverse scction on line 00 w.

This invention relates to an improvement in the construction ofsteam-boilers; and it consists in constructing a longitudinal boilerwith a downward projection below the lower level of the boiler,extending into the fire-box over the fire.

A is the boiler, constructed with a longitudinal flange, a, 011 eachside, and below the water-line, the said flanges projecting from theboiler, and so as to rest on the supportingwalls B, and leave a spacebetween the said walls and the boiler at the-flanges. (J is thefire-box, of substantially usual construction. The boiler is constructedwith an extension, A, down into the fire-box, which forms practicallythe principal heating part of the boiler, and tends to distribute orspread the flame or heat.'

This arrangement of the walls affords a considerable space for thepassage of the heat and the products of combustion around the entireexposed surface of the boiler. The front wall or bridge 'for the furnaceis left down and straight across, as at D, Fig.2, but the rear Wall Eextends up to the flange a, and conforms to the shape of the boiler,leaving onlya narrow space, cl, through which the products of combustionmust pass.

This method of suspending the boiler so as to leave an open and clearspace up to the point where the-boiler is suspended possesses a greatadvantage over the usual method of setting boilers-thatis to say, in theusual method the Wall is brought up into close contact with the boilerat the point of suspension,

thus leaving a space so narrow as to prevent all possible circulation ofheat around the adjacent portions of the boiler, and thereby confiningthe heat to the lower part of the boiler where there is sufficient roomfor circulation; but by constructing the boiler with the flanges a toextend out onto the distant walls, a clear space for circulation isattained up to these flanges, and the whole of the boiler below theflanges properly exposed to the heat from the fire, and this full effectis insured by making the forward bridge open, and closing up the rearbridge, so as to leave only a narrow space through which the products ofcombustion may pass. This tends to spread the fire, or rather draw itinto close contact with the entire exposed surface.

For the purpose of facilitating combustion, a flue, F, is arrangedacross the rear of the fire box, and above the fuel, perforated to formnumerous openings into the fire-box.

above the fuel. From this flue aconductor,f, loads to the outside of thefurnace, and a regulator or register, h, is arranged so as to vary thecapacity of the flue.

Theadvantage of mingling air w th the products of combustion, to producemore perfect combustion, .is too well known to require explanation inthis specification.

This regulated inlet is applicable to other furnacefires than that forheating steam-boilers. I therefore do not PWlSl] to be understood asconfining the invention to steam-boiler furnaces.

I do not wish to be understood as broadly claiming the construction of asteam-boiler, so that a portion of it, extending into the fire-- box,may be entirely enveloped by the products of combustion.

- I claim- In combination with the fire-box, the steamboiler arrangedlongitudinally over the firebox, and constructed with a projection, A,from the lower plane of the boiler down into the fire-box, and with anopen flue directly from the fire-box to expose the lower surface of theboiler, substantially asdescribed.

SIDNEY SMITH. Witnesses:

JOHN E. EARLE, CLARA. BROUGHTON.

